Papermakers' forming fabric including pairs of machine side complementary yarns

Abstract

A multilayer woven industrial fabric comprises at least two layers of weft yarns interwoven with at least one system of warp yarns. At least some of the machine side (MS) weft yarns are arranged as complementary pairs, such that for each pair, the members follow mutually complementary paths, and exchange positions with each other so that, in the MS surface, the path of a pair of weft yarns appears to be that of a single yarn. The complementary weft yarns interweave only with the MS warp yarns and do not appear in the paper side. The unique MS weft yarn arrangement allows for the use of smaller yarns, while increasing fabric stiffness and dimensional stability, and is applicable to any multi-layer fabric design which includes at least two layers of weft yarns and one system of warp yarns.

1 . A multilayer industrial fabric, woven according to an overall repeating weave pattern and having a paper side layer with a paper side surface and a machine side layer with a machine side surface, the fabric comprising at least one set of warp yarns and at least one set of paper side layer weft yarns and at least one set of machine side layer weft yarns, wherein at least some of the machine side layer weft yarns comprise complementary weft yarn pairs, each complementary weft yarn pair comprising a first member and a second member, which alternate with each other at exchange points to interweave only with selected warp yarns in the machine side layer such that for each complementary pair, when the first member of the pair is in the machine side surface of the fabric, the second member of the pair is carried between the machine side layer and the paper side layer. 
     
     
         2 . A fabric according to  claim 1 , wherein the machine side layer weft yarns comprise complementary weft yarn pairs and single weft yarns. 
     
     
         3 . A fabric according to  claim 2 , wherein a ratio of complementary weft yarn pairs to machine side layer weft yarns is at least 1 to 4. 
     
     
         4 . A fabric according to  claim 3 , wherein the ratio is at least 1 to 2. 
     
     
         5 . A fabric according to  claim 4 , wherein the ratio is at least 3 to 4. 
     
     
         6 . A fabric according to  claim 1 , wherein all the machine side layer weft yarns comprise complementary weft yarn pairs. 
     
     
         7 . A fabric according to  claim 1 , wherein the repeating weave pattern comprises a design selected from a double layer design, a semi duplex design, an extra support double layer design, a triple weft design, a triple layer sheet support binder design, a triple layer warp tie design and a triple layer warp integrated sheet support binder design. 
     
     
         8 . A fabric according to  claim 1 , wherein the paper side layer and the machine side layer are bound together by pairs of intrinsic weft binder yarns. 
     
     
         9 . A fabric according to  claim 8 , wherein the repeating weave pattern comprises a design selected from a double layer design, a semi duplex design, an extra support double layer design, a triple weft design, and a triple layer sheet support binder design. 
     
     
         10 . A fabric according to  claim 9 , wherein the repeating weave pattern comprises a triple layer sheet support binder design. 
     
     
         11 . A fabric according to  claim 1 , wherein the paper side layer and the machine side layer are bound together by pairs of intrinsic warp binder yarns. 
     
     
         12 . A fabric according to  claim 11 , wherein the repeating weave pattern comprises a design selected from a double layer design, a semi duplex design, an extra support double layer design, a triple weft design, a triple layer warp tie design and a triple layer warp integrated sheet support binder design. 
     
     
         13 . A fabric according to  claim 12 , wherein the repeating weave pattern comprises a triple layer warp integrated sheet support binder design. 
     
     
         14 . A fabric according to  claim 1 , wherein each exchange point is located over a number of warp yarns in the machine side layer selected from 0, 1, 2 and 3. 
     
     
         15 . A fabric according to  claim 1 , wherein the complementary weft yarn pairs are polymeric monofilaments constructed of a material selected from polyesters, polyamides and blends thereof, and polymer blends. 
     
     
         16 . A fabric according to  claim 15 , wherein the material is a polyester selected from polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and copolymers and blends thereof. 
     
     
         17 . A fabric according to  claim 15 , wherein the material is a polyamide selected from polyamide-6, polyamide-66, polyamide-6/10, polyamide-6/12. 
     
     
         18 . A fabric according to  claim 15 , wherein the material is a polymer comprising a blend of thermoplastic polyurethane and polyester. 
     
     
         19 . A fabric according to  claim 1 , wherein each member of each complementary weft yarn pair has a cross-sectional shape selected from one of circular, elliptical, rectangular and square. 
     
     
         20 . A fabric according to  claim 1 , wherein the fabric is a papermakers' forming fabric.